U.S. patent number 9,474,536 [Application Number 14/266,075] was granted by the patent office on 2016-10-25 for apparatus and methods for removing vertebral bone and disc tissue.
This patent grant is currently assigned to BOSTON SCIENTIFIC SCIMED, INC.. The grantee listed for this patent is Boston Scientific Scimed, Inc.. Invention is credited to Harold F. Carrison, Stanley W. Olson, Jr., Mukund R. Patel.
United States Patent |
9,474,536 |
Carrison , et al. |
October 25, 2016 |
Apparatus and methods for removing vertebral bone and disc
tissue
Abstract
Tissue removal probes comprise an elongated member, a drive
shaft rotatably disposed within the member, and a rotatably tissue
removal element mounted to the distal end of the drive shaft. One
tissue removal element comprises a plurality of tissue-cutting
filaments affixed at proximal and distal ends of the tissue removal
element. The cutting filaments may have optional hinge points that
allow the distal end of the tissue removal element to be inverted,
thereby transforming the tissue removal element from a
tissue-cutting device to a tissue-grasping device. Another tissue
removal element may have a blunted tip to prevent distal tissue
trauma and an irrigation port to provide irrigation fluid to the
removed tissue and/or tissue removal element. Another tissue
removal element has a proximal and distal spiral grooves that are
oppositely pitched, so that removed tissue can be collected in the
middle of the tissue removal element. Another tissue removal
element has independent counter-rotating tissue removal elements to
maintain stability during a bone cutting procedure. Still another
tissue removal element takes the form of a drill bit with fluted
cutting grooves. Yet another tissue removal element has cascading
tissue-cutting notches that can be reciprocatably moved to remove
tissue within a hole.
Inventors: |
Carrison; Harold F.
(Pleasanton, CA), Patel; Mukund R. (San Jose, CA), Olson,
Jr.; Stanley W. (Germantown, TN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Boston Scientific Scimed, Inc. |
Maple Grove |
MN |
US |
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Assignee: |
BOSTON SCIENTIFIC SCIMED, INC.
(Maple Grove, MN)
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Family
ID: |
34919748 |
Appl.
No.: |
14/266,075 |
Filed: |
April 30, 2014 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20140324052 A1 |
Oct 30, 2014 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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10793185 |
Mar 3, 2004 |
8784421 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B
17/1671 (20130101); A61B 17/32002 (20130101); A61B
17/1615 (20130101); A61B 17/1633 (20130101); A61B
17/1617 (20130101); A61B 17/1631 (20130101); A61B
17/1604 (20130101); A61B 17/221 (20130101); A61B
2017/003 (20130101); A61B 2017/22038 (20130101); A61B
2017/00261 (20130101); A61B 2217/007 (20130101); A61B
17/320725 (20130101); A61B 2017/320032 (20130101); A61B
2217/005 (20130101); A61B 2017/320028 (20130101); A61B
17/1662 (20130101) |
Current International
Class: |
A61B
17/32 (20060101); A61B 17/16 (20060101); A61B
17/221 (20060101); A61B 17/3207 (20060101); A61B
17/22 (20060101); A61B 17/00 (20060101) |
Field of
Search: |
;606/170,180,114,171,181-183 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0086048 |
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Aug 1983 |
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EP |
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WO-0160264 |
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Aug 2001 |
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WO |
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WO-0203870 |
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Jan 2002 |
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WO |
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Other References
Advisory Action mailed Mar. 12, 2007 for U.S. Appl. No. 10/872,097,
filed Jun. 17, 2004. cited by applicant .
Amendment and Response Submitted with RCE to Final Office Action
submitted Feb. 12, 2008 for U.S. Appl. No. 10/872,097. cited by
applicant .
Amendment and Response Submitted with RCE to Final Office Action
submitted Mar. 16, 2007 for U.S. Appl. No. 10/872,097. cited by
applicant .
Amendment and Response Submitted with RCE to Final Office Action
mailed Apr. 27, 2007 for U.S. Appl. No. 10/793,693. cited by
applicant .
Amendment and Response to Non-Final Office Action submitted Oct. 6,
2008 for U.S. Appl. No. 10/793,693. cited by applicant .
Amendment and Response to Non-Final Office Action submitted Jul.
16, 2008 for U.S. Appl. No. 10/872,097. cited by applicant .
Amendment and Response to Non-Final Office Action submitted Aug.
17, 2007 for U.S. Appl. No. 10/872,097. cited by applicant .
Amendment and Response to Non-Final Office Action submitted Feb.
28, 2008 for U.S. Appl. No. 10/793,693. cited by applicant .
Appeal Brief mailed Apr. 17, 2009 for U.S. Appl. No. 10/872,097,
filed Jun. 17, 2004. cited by applicant .
Final Office Action mailed Jan. 9, 2009 for U.S. Appl. No.
10/793,693. cited by applicant .
Final Office Action mailed Dec. 12, 2006 for U.S. Appl. No.
10/872,097. cited by applicant .
Final Office Action mailed Nov. 14, 2007 for U.S. Appl. No.
10/872,097. cited by applicant .
Final Office Action mailed Apr. 27, 2007 for U.S. Appl. No.
10/793,693. cited by applicant .
Final Office Action mailed Oct. 28, 2008 for U.S. Appl. No.
10/872,097. cited by applicant .
Non-Final Office Action mailed Nov. 7, 2006 for U.S. Appl. No.
10/793,693. cited by applicant .
Non-Final Office Action mailed Jul. 9, 2008 for U.S. Appl. No.
10/793,693. cited by applicant .
Non-Final Office Action mailed May 18, 2007 for U.S. Appl. No.
10/872,097. cited by applicant .
Non-Final Office Action mailed May 19, 2006 for U.S. Appl. No.
10/872,097. cited by applicant .
Non-Final Office Action mailed Mar. 25, 2008 for U.S. Appl. No.
10/872,097. cited by applicant .
Non-Final Office Action mailed Oct. 29, 2007 for U.S. Appl. No.
10/793,693. cited by applicant .
Pre-Appeal Brief Conference Decision mailed Apr. 1, 2009 for U.S.
Appl. No. 10/872,097. cited by applicant .
Pre-Appeal Brief Conference Decision mailed Apr. 27, 2009 for U.S.
Appl. No. 10/793,693. cited by applicant .
Pre-Appeal Brief Request for Review submitted Mar. 25, 2009 for
U.S. Appl. No. 10/793,693. cited by applicant .
Pre-Appeal Brief Request for Review submitted Jan. 28, 2009 for
U.S. Appl. No. 10/872,097. cited by applicant .
Response to Office Action submitted Dec. 12, 2006 for U.S. Appl.
No. 10/872,097. cited by applicant .
Response to Non-Final Office Action submitted Sep. 19, 2006 for
U.S. Appl. No. 10/872,097. cited by applicant .
Response to Non-Final Office Action submitted Jan. 25, 2007 for
U.S. Appl. No. 10/793,693. cited by applicant.
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Primary Examiner: Hoffman; Mary
Assistant Examiner: Carter; Tara R
Attorney, Agent or Firm: Seager, Tufte & Wickhem,
LLP
Parent Case Text
RELATED APPLICATIONS
This application is a Continuation Application of U.S. patent
application Ser. No. 10/793,185, filed Mar. 3, 2004, now U.S. Pat.
No. 8,784,421, issued Jul. 22, 2014, which is related to
application Ser. No. 10/793,694, filed Mar. 3, 2004, now abandoned,
application Ser. No. 10/793,693, filed Mar. 3, 2004, now abandoned,
and application Ser. No. 10/793,690, filed Mar. 3, 2004, now
abandoned, all of which are expressly incorporated herein by
reference.
Claims
The invention claimed is:
1. A tissue removal probe, comprising: a multi-lumen elongated
member having a working channel, a distal end region, and a distal
end, the distal end region of the elongated member including a
window cutout extending therethrough, the window cutout being
positioned proximally of the distal end of the elongated member,
wherein the elongated member further includes at least one lumen
configured for coupling to a source of at least one of irrigation
and/or aspiration fluid; a drive shaft rotatably disposed within
the working channel; and a rotatable tissue removal element mounted
to a distal end of the drive shaft, the tissue removal element
being aligned with the window cutout, the tissue removal element
having a plurality of tissue-cutting structures configured to
resect tissue as the drive shaft rotates the tissue removal
element.
2. The tissue removal probe of claim 1, wherein the rotatable
tissue removal element includes a rotatable burr.
3. The tissue removal probe of claim 2, wherein the burr includes a
non-traumatic blunt tip.
4. The tissue removal probe of claim 3, further including: a
channel extending through the drive shaft and the burr, and
terminating at the blunt tip, wherein the channel is configured to
convey irrigation fluid and/or a guidewire therethrough.
5. The tissue removal probe of claim 2, wherein the burr includes a
cutting groove configured to convey resected tissue proximally.
6. The tissue removal probe of claim 2, wherein the burr includes
counter-pitched grooves.
7. The tissue removal probe of claim 1, wherein the rotatable
tissue removal element includes a plurality of tissue-cutting
filaments.
8. The tissue removal probe of claim 7, wherein the plurality of
tissue-cutting filaments form a basket.
9. The tissue removal probe of claim 7, wherein each of the
plurality of tissue-cutting elements has a sinusoidal shape.
10. The tissue removal probe of claim 7, wherein the rotatable
tissue removal element includes at least three tissue-cutting
filaments.
11. The tissue removal probe of claim 7, wherein the plurality of
tissue-cutting elements is configured to transition between a
basket configuration and a grasper configuration.
12. A tissue removal probe, comprising: a multi-lumen elongated
member having a working channel, a distal end region of the
elongated member including a window cutout extending therethrough,
the window cutout being axially spaced from a distalmost end of the
elongated member, wherein the elongated member further includes a
first lumen configured for coupling to a source of irrigation fluid
and a second lumen configured for coupling to a source of
aspiration, and wherein at least one of the first lumen and second
lumen terminate at the distal end of the elongated member; a drive
shaft rotatably disposed within the working channel; and a
rotatable tissue removal element mounted to a distal end of the
drive shaft, the tissue removal element being aligned with the
window cutout, the tissue removal element having a plurality of
tissue-cutting filaments extending distally of the drive shaft and
configured to resect tissue as the drive shaft rotates the tissue
removal element.
13. The tissue removal probe of claim 12, wherein the plurality of
tissue-cutting filaments form a basket.
14. The tissue removal probe of claim 12, wherein the rotatable
tissue removal element includes at least three tissue-cutting
filaments.
15. The tissue removal probe of claim 12, wherein the plurality of
tissue-cutting filaments is configured to transition between a
basket configuration and a grasper configuration.
16. A tissue removal probe, comprising: a multi-lumen elongated
member having a working channel, a distal end region, and a distal
end, the distal end region of the elongated member including a
window cutout extending therethrough, the window cutout being
positioned proximally of the distal end of the elongated member,
wherein the elongated member further includes a first lumen
configured for coupling to a source of irrigation fluid and a
second lumen configured for coupling to a source of aspiration, and
wherein at least one of the first lumen and second lumen terminate
at the distal end of the elongated member; a drive shaft rotatably
disposed within the working channel; and a rotatable tissue removal
element mounted to a distal end of the drive shaft, the tissue
removal element being aligned with the window cutout, the tissue
removal element including a burr extending distally of the drive
shaft and configured to resect tissue as the drive shaft rotates
the tissue removal element.
17. The tissue removal probe of claim 16, wherein the burr includes
a non-traumatic blunt tip.
18. The tissue removal probe of claim 17, further including: a
channel extending through the drive shaft and the burr, and
terminating at the blunt tip, wherein the channel is configured to
convey irrigation fluid and/or a guidewire therethrough.
19. The tissue removal probe of claim 16, wherein the burr includes
a cutting groove configured to convey resected tissue
proximally.
20. The tissue removal probe of claim 16, wherein the burr includes
counter-pitched grooves.
Description
FIELD OF THE INVENTION
The field of the invention pertains to medical devices and methods
for removing tissue, and in particular, vertebral bone and
intervertebral disc tissue.
BACKGROUND OF THE INVENTION
The spinal column consists of thirty-three bones called vertebra,
the first twenty-four vertebrae of which make up the cervical,
thoracic, and lumbar regions of the spine and are separated from
each other by "pads" of tough cartilage called "intervertebral
discs," which act as shock absorbers that provide flexibility,
stability, and pain-free movement of the spine.
FIGS. 1 and 2 illustrate a portion of a healthy and normal spine,
and specifically, two vertebra 10 and two intervertebral discs 12
(only one shown). The posterior of the vertebra 10 includes right
and left transverse processes 14R, 14L, right and left superior
articular processes 16R, 16L, and a spinous process 18. Muscles and
ligaments that move and stabilize the vertebra 10 are connected to
these structures. The vertebra 10 further includes a centrally
located lamina 20 with right and left lamina 20R, 20L, that lie
inbetween the spinous process 18 and the superior articular
processes 16R, 16L. Right and left pedicles 22R, 22L are positioned
anterior to the right and left transverse processes 14R, 14L,
respectively. A vertebral arch 24 extends between the pedicles 22
and through the lamina 20. The anterior of the vertebra 10 includes
a vertebral body 26, which joins the vertebral arch 24 at the
pedicles 22. The vertebral body 26 includes an interior volume of
reticulated, cancellous bone (not shown) enclosed by a compact
cortical bone 30 around the exterior. The vertebral arch 24 and
vertebral body 26 make up the spinal canal (i.e., the vertebral
foramen 32), which is the opening through which the spinal cord 34
and epidural veins (not shown) pass. Nerve roots 36 laterally pass
from the spinal cord 34 out through the neural foramen 38 at the
side of the spinal canal formed between the pedicles 22.
Structurally, the intervertebral disc 12 consists of two parts: an
inner gel-like nucleus (nucleus pulposus) 40 located centrally
within the disc 12, and tough fibrous outer annulus (annulus
fibrosis) 42 surrounding the nucleus 40.
A person may develop any one of a variety of debilitating spinal
conditions and diseases. For example, as illustrated in FIG. 3,
when the outer wall of the disc 12' (i.e., the annulus fibrosis 42)
becomes weakened through age or injury, it may tear allowing the
soft inner part of the disc 12 (i.e., the nucleus pulposus 40) to
bulge out, forming a herniation 46. The herniated disc 12' often
pinches or compresses the adjacent dorsal root 36 against a portion
of the vertebra 10, resulting in weakness, tingling, numbness, or
pain in the back, legs or arm areas.
Often, inflammation from disc herniation can be treated
successfully by nonsurgical means, such as bedrest, therapeutic
exercise, oral anti-inflammatory medications or epidural injection
of corticosteroids, and anesthetics. In some cases, however, the
disc tissue is irreparably damaged, in which case, surgery is the
best option.
Discectomy, which involves removing all, or a portion, of the
affected disc, is the most common surgical treatment for ruptured
or herniated discs of the lumbar spine. In most cases, a laminotomy
or laminectomy is performed to visualize and access the affected
disc. Once the vertebrae, disc, and other surrounding structures
can be visualized, the surgeon will remove the section of the disc
that is protruding from the disc wall and any other offending disc
fragments that may have been expelled from the disc. In some cases,
the entire disc may be removed, with or without a bony fusion or
arthroplasty (disc nucleus replacement or total disc
replacement).
Open discectomy is usually performed under general anesthesia and
typically requires at least a one-day hospital stay. During this
procedure, a two to three-inch incision in the skin over the
affected area of the spine is made. Muscle tissue may be separated
from the bone above and below the affected disc, while retractors
hold the wound open so that the surgeon has a clear view of the
vertebrae and disc and related structures. The disc or a portion
thereof, can then be removed using standard medical equipment, such
as rongeurs and curettes.
Because open discectomy requires larger incisions, muscle stripping
or splitting, more anesthesia, and more operating, hospitalization,
and a longer patient recovery time, the trend in spine surgery is
moving towards minimally invasive surgical techniques, such as
microdiscectomy and percutaneous discectomy.
Microdiscectomy uses a microscope or magnifying instrument to view
the disc. The magnified view may make it possible for the surgeon
to remove herniated disc material through a smaller incision (about
twice as small as that required by open discectomy) with smaller
instruments, potentially reducing damage to tissue that is intended
to be preserved.
Percutaneous discectomy is often an outpatient procedure that may
be carried out by utilizing hollow needles or cannulae through
which special instruments can be deployed into the vertebra and
disc in order to cut, remove, irrigate, and aspirate tissue. X-ray
pictures and a video screen and computer-aided workstation may be
used to guide by the surgeon into the treatment region. Improved
imaging and video or computer guidance systems have the potential
to reduce the amount of tissue removal required to access and treat
the injured tissue or structures. Sometimes an endoscope is
inserted to view the intradiscal and perivertebral area.
Besides disc hernias, other debilitating spinal conditions or
diseases may occur. For example, spinal stenosis, which results
from hypertrophic bone and soft tissue growth on a vertebra,
reduces the space within the spinal canal. When the nerve roots are
pinched, a painful, burning, tingling, and/or numbing sensation is
felt down the lower back, down legs, and sometimes in the feet. As
illustrated in FIG. 2, the spinal canal 32 has a rounded triangular
shape that holds the spinal cord 34 without pinching. The nerve
roots 36 leave the spinal canal 32 through the nerve root canals
38, which should be free of obstruction. As shown in FIG. 4,
hypertrophic bone growth 48 (e.g., bone spurs, osteophytes,
spondylophytes) within the spinal canal 32, and specifically from
the diseased lamina 20 and proximate facet joints may cause
compression of the nerve roots, which may contribute or lead to the
pain of spinal stenosis. Spinal stenosis may be treated by
performing a laminectomy or laminectomy in order to decompress the
nerve root 36 impinged by the bone growth 48. Along with the
laminectomy, a foraminotomy, (i.e., enlarging of the channel from
which the nerve roots 36 exit is performed). Depending on the
extent of the bone growth, the entire lamina and spinal process may
be removed.
Another debilitating bone condition is a vertebral body compression
fracture (VCF), which may be caused by spinal injuries, bone
diseases such as osteoporosis, vertebral hemangiomas, multiple
myeloma, necrotic lesions (Kummel's Disease, Avascular Necrosis),
and metastatic disease, or other conditions that can cause painful
collapse of vertebral bodies. VCFs are common in patients who
suffer from these medical conditions, often resulting in pain,
compromises to activities of daily living, and even prolonged
disability.
On some occasions, VCFs may be repaired by cutting, shaping, and
removing damaged bone tissue inside a vertebra to create a void,
and then injecting a bone cement percutaneously or packing bone
graft into the void. This is typically accomplished percutaneously
through a cannula to minimize tissue trauma. The hardening
(polymerization) of a bone cement media or bone grafting or other
suitable biomaterial serves to buttress the bony vault of the
vertebral body, providing both increased structural integrity and
decreased pain that may be associated with micromotion and
progressive collapse of the vertebrae.
Thus, it can be appreciated that in many spinal treatment
procedures, bone and/or disc tissue must be removed in order to
decompress neural tissue or rebuild the bony vertebra or
intervertebral disc. In the case of target bone tissue that is
adjacent spinal tissue, a physician is required to exercise extreme
care when cutting away the target bone tissue (e.g., during a
laminectomy and foraminotomy), such that injury to spinal tissue
can be prevented. A physician may have difficulty controlling
existing bone removal devices, however, and may unintentionally
remove healthy bone tissue or injure spinal tissue during use. This
problem is exacerbated with percutaneous treatments, which,
although less invasive than other procedures, limit the range of
motion of the cutting instrument, thereby further limiting the
control that the physician may have during the bone cutting
procedure.
Burr-type tissue removal probes may also be used to remove soft
tissue, such as the gel-like nuclear tissue within the
intervertebral disc or the cancellous bone tissue within the
vertebral body. For example, FIG. 5 illustrates one prior art
burr-type tissue removal probe 50 that can be introduced through a
delivery cannula (not shown) into contact with the target tissue
region to be removed. The tissue removal probe 50 comprises a rigid
shaft 52 and a rotatable burr 54 associated with the distal end of
the rigid shaft 52. Rotation of a drive shaft 56 extending through
the rigid shaft 52, in turn, causes rotation of the burr 54 (either
manually or via a motor), thereby removing tissue that comes in
contact with the burr 54. Notably, the tissue removal probe 50 is
laterally constrained within the cannula (or if a cannula is not
shown, constrained by the many layers of tissue that the device 50
must traverse to reach the target tissue), and thus, can only be
effectively moved along its longitudinal axis, thereby limiting the
amount of tissue that can be removed to the tissue that is on-axis.
As such, the tissue removal probe 50 may have to be introduced
through several access points within the anatomical body (e.g., the
disc or vertebral body) that contains the target tissue in order to
remove the desired amount of the tissue.
As illustrated in FIG. 6, the distal end 58 of the rigid shaft 52
may be curved in an alternative prior art removal device 60, so
that the burr 54 is off-axis from the shaft 52. As such, off-axis
target regions can be reached by rotating and axially displacing
the rigid shaft 52 about its axis. Because the length of the curved
distal end is fixed, however, only the tissue regions that are
off-axis by a distance equal to the off-axis distance of the burr
54 will be removed, as illustrated in FIG. 7. In effect, the
removal device 60 can only remove a cylindrical outline 62 of the
tissue, leaving a cylindrical tissue body 64 behind. Thus, the
tissue removal probe 60 must still be introduced into the tissue
via several access holes in order to remove any remaining
tissue.
In addition, because the distal end of the rigid shaft 52 is curved
and has a length of the distal tip that is now at an angle to the
main shaft, the delivery cannula must be made larger to accommodate
the entire profile of the distal end. Thus, the incision through
which the cannula is introduced must likewise be made larger.
Lastly, if the anatomical body in which the removal device 60 is
introduced is relatively thin (e.g., an intervertebral disc is a
few millimeters thick), the top or bottom of the anatomical body
may hinder movement of the burr 54 as the shaft 52 is rotated
around its axis. In such cases, the removal device 60 may have to
be introduced along the bottom of the anatomical body to allow
tissue to be removed at the top of the anatomical body (i.e., by
sweeping the burr 54 along an upper arc until the burr 54 hits the
top, or if clearance at the top is available, by sweeping the burr
54 along the upper arc, below the top, until the burr 54 hits the
bottom), and then reintroduced along the top of the anatomical body
to allow tissue to be removed at the bottom of the anatomical body
(i.e., by sweeping the burr 54 along a lower arc until the burr 54
hits the bottom, or if clearance at the bottom is available, by
sweeping the burr 54 along the lower arc, above the bottom, until
the burr 54 hits the top). As can be appreciated, this excessive
movement of the removal device 60 increases the time of the spinal
procedure as well as surgical risk due to manipulation of the
device.
Another problem with current burr-type removal devices is that soft
material, such as the nuclear material in an intervertebral disc or
cancellous bone within the vertebral body, tends to stick to the
burrs, thereby limiting the abrasive effect that the burrs are
intended to have in order to efficiently remove tissue. As a
result, burr-type removal device may have to be continuously
removed from the patient's body in order to clean the soft tissue
from the burr.
Furthermore, during the tissue removal or cutting process, a media,
such as saline, is generally delivered via a tube to a target site
for clearing debris. The delivered media together with the debris
are then removed from the target site via a separate tube (i.e.,
the media and the debris are aspirated into a vacuum port of the
tube). When the spine is treated percutaneously, however, the
delivery cannula must be made large enough to accommodate the
tissue removal probe and tubes. As a result, the incision through
which the cannula is to be introduced must be made relatively
large, thereby unnecessarily causing more tissue trauma.
There, thus, remains a need to provide for improved tissue removal
probes and methods for use during spinal treatment and other
surgeries.
SUMMARY OF THE INVENTION
The present inventions are directed to tissue removal probes that
are capable of removing tissue, such as vertebral bone tissue,
although such tissue removal probes may be used to remove tissue
from other bone structure, such as the skull, humerus, radius,
ulna, femur, fibula, tibia, hip bone, and bones within the hands
and feet. In addition, some of the tissue removal probes lend
themselves well to the removal of soft tissue, such as cancellous
bone or intervertebral disc tissue. Some of the tissue removal
probes also lends themselves to laterally cutting bone tissue,
e.g., in a laminectomy procedure. The tissue removal probes of the
present inventions comprise an elongated member (such as a sleeve)
having a lumen, a drive shaft rotatably disposed within the member
lumen, and a rotatably tissue removal element mounted to the distal
end of the drive shaft. They may be combined into a tissue removal
assembly that includes a cannula in which the tissue removal probe
can be slidably disposed.
In accordance with a first aspect of the present invention, the
tissue removal element comprises a plurality of tissue-cutting
filaments affixed at proximal and distal ends of the tissue removal
element. In one embodiment, the tissue removal element comprises a
base member mounted to the distal end of the drive shaft and a
distal hub. The filaments are connected between the base member and
the distal hub. The filaments can be variously configured. In one
embodiment, the filaments are interlaced, e.g., to provide the
tissue removal element with increased structural integrity. In
another embodiment, the filaments are looped. The tissue removal
element may further include abrasive particles disposed on the
filaments. The tissue removal probe optionally comprises a proximal
adapter mounted to the member for mating with a drive unit. The
tissue removal probe may optionally comprise a guide wire extending
through the tissue removal element in order to provide lateral
support. By way of non-limiting example, the large spaces formed
between the tissue-cutting filaments prevents or minimizes the
build up of tissue on the tissue removal element.
In accordance with a second aspect of the present inventions, the
tissue-cutting filaments have hinge points that divide the
filaments into proximal filament segments and distal filament
segments. The tissue removal probe further comprises a pull element
mounted to the distal end of the tissue removal element. Pulling
the pull element causes the distal filament segments to hinge
towards the proximal filament segments to form folded filaments
configured to be used as tissue-grasping arms. In this manner, the
tissue removal element can be either used as a tissue-cutting
device or a tissue-grasping device. In one embodiment, the hinge
points can be located distal of the filament midpoints, so as to
make the tissue-grasping arms shorter, thus increasing their
lateral strength. In one embodiment, the pulling of the pull
element causes the distal end of the tissue removal element to
invert. The pull element may be slidably disposed in a lumen within
the drive shaft.
In accordance with a third aspect of the present inventions, the
drive shaft is rigid and has a distal end with a blunt tip, e.g., a
spherical tip. In this manner, inadvertent tissue trauma distal to
the tissue removal element is prevented or minimized. The tissue
removal probe further comprises a lumen extending through the drive
shaft and terminating in a flush port at the blunt tip. In this
manner, a convenient means of providing irrigation fluid to the
tissue and/or tissue removal element is provided. The tissue
removal element can take the form of any element, but in one
embodiment, it is an abrasive burr. A spiral cutting groove can be
provided on the tissue removal element, so as to facilitate
movement of the removed tissue in the proximal direction. The
optional proximal adapter may be configured for mating with both a
drive unit and an irrigation source.
In accordance with a fourth aspect of the present inventions, the
tissue removal element has a proximal spiral groove and a distal
spiral groove. The proximal and distal spiral grooves are
oppositely pitched. By way of non-limiting example, the oppositely
pitched spiral grooves provides a convenient means for collecting
the removed tissue. In particular, the removed tissue will be
forced to move along the grooves to the center of the tissue
removal element when rotated in a particular direction.
In accordance with a fifth aspect of the present inventions, the
drive shaft can be an outer drive shaft with a lumen. The tissue
removal device also has an inner drive shaft rotatably disposed
within the outer drive shaft lumen. In this manner, the outer and
inner drive shaft may rotate independently relative to each other,
e.g., in opposite directions or in the same direction. The tissue
removal probe comprises two tissue removal elements--one mounted to
the outer drive shaft, and the other mounted to the inner drive
shaft. The tissue removal elements may be in a proximal and distal
relationship and may be coextensive with each other, so that the
tissue removal elements effectively act as one tissue removal
element. By way of non-limiting example, the independent rotation
of the drive shafts provides a convenient means for rotating the
two tissue removal elements in opposite directions or in the same
direction.
The tissue removal elements may take the form of any element, but
in one embodiment, they take the form of two separate burrs. The
tissue removal elements may advantageously have oppositely pitched
spiral cutting grooves. In this manner, when rotated in opposite
directions, the cutting action of the tissue removal elements is
steadier, and minimizes stray from the cutting line. When rotated
in the same direction, the removed tissue is forced to travel along
the cutting grooves to the interface between the tissue removal
elements, where it can be collected and aspirated.
In accordance with a sixth aspect of the present inventions, the
tissue removal probe may comprise a rigid shaft and a drill bit
formed on the distal end of the rigid shaft. The rigid shaft may be
slidably disposed within a cannula lumen, in which case, the sheath
may be optional. The drill bit has two fluted cutting grooves
longitudinally extending along opposite sides of the drill bit. In
this manner, the drill bit can be used to drill through bone
tissue.
In accordance with a seventh aspect of the present inventions, the
tissue removal element takes the form of a block on which a series
of longitudinally disposed cascading tissue-cutting notches are
disposed. By way of non-limiting example, the tissue removal
element can be used to enlarge holes, grooves, channels or shaped
defined by the tissue-cutting notches within bones by placing the
tissue removal element within the hole and applying a reciprocating
motion to the drive shaft to in order to remove tissue with the
cutting notches.
Other and further aspects and features of the invention will be
evident from reading the following detailed description of the
preferred embodiments, which are intended to illustrate, not limit,
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings illustrate the design and utility of preferred
embodiments of the present invention. It should be noted that the
figures are not drawn to scale and that elements of similar
structures or functions are represented by like reference numerals
throughout the figures. In order to better appreciate how the
above-recited and other advantages and objects of the present
inventions are obtained, a more particular description of the
present inventions briefly described above will be rendered by
reference to specific embodiments thereof, which are illustrated in
the accompanying drawings. Understanding that these drawings depict
only typical embodiments of the invention and are not therefore to
be considered limiting of its scope, the invention will be
described and explained with additional specificity and detail
through the use of the accompanying drawings in which:
FIG. 1 is a perspective view of a portion of a spine;
FIG. 2 is a top view of a vertebra with a healthy intervertebral
disc;
FIG. 3 is a top view of a vertebra with a herniated intervertebral
disc;
FIG. 4 is a top view of a vertebra with spinal stenosis;
FIG. 5 is a prior art tissue removal probe;
FIG. 6 is another prior art tissue removal probe;
FIG. 7 is a plan view showing tissue removal using the tissue
removal probe of FIG. 6;
FIG. 8 is a perspective view of a tissue removal system arranged in
accordance with a preferred embodiment of the present
invention;
FIG. 9 is perspective view of a tissue removal probe that can be
used in the system of FIG. 8;
FIG. 10 is a partially cutaway side view of the distal end of the
probe of FIG. 9, particularly showing the tissue removal element
retracted within the probe shaft;
FIG. 11 is a partially cutaway side view of the distal end of the
probe of FIG. 9, particularly showing the tissue removal element
partially deployed from the probe shaft;
FIG. 12 is a partially cutaway side view of the distal end of the
probe of FIG. 9, particularly showing the tissue removal element
fully deployed from the probe shaft;
FIG. 13 is a perspective view of a variation of the probe of FIG.
9, particularly showing irrigation and aspiration lumens;
FIGS. 14A-14G are perspective views showing a method of using the
tissue removal system of FIG. 8 to remove tissue within a herniated
intervertebral disc;
FIG. 15 is a partially cutaway side view of the distal end of
another tissue removal probe that can be used in the tissue removal
system of FIG. 8, particularly showing the tissue removal element
retracted within the probe shaft;
FIG. 16 is a partially cutaway side view of the distal end of the
probe of FIG. 15, particularly showing the tissue removal element
partially deployed from the probe shaft;
FIG. 17 is a partially cutaway side view of the distal end of the
probe of FIG. 15, particularly showing the tissue removal element
fully deployed from the probe shaft;
FIG. 18 is perspective view of still another tissue removal probe
that can be used in the system of FIG. 8;
FIG. 19 is a partially cut-away side view of the distal end of the
probe of FIG. 18, particularly showing a tissue removal
element;
FIG. 20 is a partially cut-away side view of a variation of the
distal end of the probe of FIG. 18, particularly showing a
variation of the tissue removal element;
FIG. 21 is perspective view of yet another tissue removal probe
that can be used in the system of FIG. 8;
FIGS. 22A-22D are side views of the distal end of the probe of FIG.
21, particularly showing a transformation of the probe from a
tissue-cutting device to a tissue-grasping device;
FIG. 23 is perspective view of yet another tissue removal probe
that can be used in the system of FIG. 8;
FIG. 24 is a partially cut-away side view of the distal end of the
probe of FIG. 23;
FIG. 25 is perspective view of yet another tissue removal probe
that can be used in the system of FIG. 8;
FIG. 26 is a partially cut-away side view of the distal end of yet
another tissue removal probe that can be used in the system of FIG.
8;
FIG. 27 is perspective view of yet another tissue removal probe
that can be used in the system of FIG. 8;
FIG. 28 is a cross-sectional view of the probe of FIG. 27, taken
along the line 28-28;
FIG. 29 is perspective view of yet another tissue removal probe
that can be used in the system of FIG. 8;
FIG. 30 is a partially cutaway side view of the distal end of still
another tissue removal probe that can be used in the tissue removal
system of FIG. 8, particularly showing the tissue removal element
retracted within the probe shaft;
FIG. 31 is a cross-sectional view of the distal end of the tissue
removal probe of FIG. 30, taken along the line 31-31;
FIG. 32 is a partially cutaway side view of the distal end of the
probe of FIG. 30, particularly showing the tissue removal element
partially deployed from the probe shaft;
FIG. 33 is a partially cutaway side view of the distal end of the
probe of FIG. 30, particularly showing the tissue removal element
fully deployed from the probe shaft; and
FIGS. 34A-34D are perspective views showing a method of using the
tissue removal system of FIG. 8, with the tissue removal probe of
FIG. 30, to remove tissue within a herniated intervertebral
disc.
DETAILED DESCRIPTION OF THE EMBODIMENTS
FIG. 8 illustrates a tissue removal system 100 constructed in
accordance with a preferred embodiment of the present inventions.
The system 100 generally comprises a tissue removal probe assembly
102 and a rotary drive unit 104 connected to the probe assembly 102
via a drive cable 106. The drive unit 104 may take the form of a
standard rotary drive used for powering medical cutting
instruments. The tissue removal probe assembly 102 comprises a
cannula 108 and a tissue removal probe 110 disposed therein.
The cannula 108 comprises a shaft 112 having a distal end 114 and
proximal end 116, a lumen 118 (shown in phantom) terminating in an
exit port 120 at the distal end 114 of the cannula shaft 112, and a
handle 122 mounted on the proximal end 116 of the cannula shaft
112. To facilitate introduction through tissue, the cannula shaft
112 is preferably stiff (e.g., it can be composed of a stiff
material, or reinforced with a coating or a coil to control the
amount of flexing), so that the cannula shaft 112 can penetrate the
tissue without being damaged. The materials used in constructing
the cannula shaft 112 may comprise any of a wide variety of
biocompatible materials. In a preferred embodiment, a radiopaque
material, such as metal (e.g., stainless steel, titanium alloys, or
cobalt alloys) or a polymer (e.g., ultra high molecular weight
polyethylene) may be used, as is well known in the art.
Alternatively, if supported by a rigid member during introduction
into the tissue, the cannula shaft 112 may be flexible. The handle
122 is preferably composed of a durable and rigid material, such as
medical grade plastic, and is ergonomically molded to allow a
physician to more easily manipulate the cannula 108.
The outer diameter of the cannula shaft 112 is preferably less than
1/2 inch, but other dimensions for the outer diameter of the
cannula shaft 112 may also be appropriate, depending on the
particular application or clinical procedure. The cannula lumen 118
should have an inner diameter so as to allow the tissue removal
probe 110 to be slidably housed therein, as will be described in
further detail below. In the illustrated embodiment, the profile of
the cannula lumen 118 is circular, but can be other shapes as well.
In the illustrated embodiment, the distal tip of the cannula shaft
112 is blunt. In this case, the thickness and cross-sectional
profile of the cannula shaft 112 is small enough, so that the
distal tip can be used as a cutting or deforming tool for boring or
coring through tissue. Alternatively, the distal tip of the cannula
shaft 112 may be advantageously sharpened or wedged to facilitate
its introduction into bone structure. Even more alternatively, a
stilette (not shown) can be introduced through the cannula lumen
118 to provide an independent means for boring through bone
structure. In this manner, bone cores will not block the cannula
lumen 118, which may otherwise prevent, or at least make difficult,
deployment of the tissue removal probe 110 and other therapeutic
materials.
Referring now to FIG. 9, the tissue removal probe 110 will
described in further detail. The tissue removal probe 110 comprises
a sleeve 124 having a distal end 126 and a proximal end 128, and a
lumen 130 (shown in phantom) extending through the sleeve 124. The
tissue removal probe 110 further comprises a drive shaft 132
rotatably disposed within the sleeve lumen 130 and a rotatable
tissue removal element, and in particular, an abrasive burr 134,
mounted to the distal end of the drive shaft 132. The burr 134 has
a pattern of cutting edges 136 that facilitate removal of tissue
that comes in contact with the rotating burr 134. In the
illustrated embodiment, the burr 134 is fully exposed in that it
entirely resides outside of the sleeve 124. In alternative
embodiments, the burr 134 may be seated within the distal end of a
sheath, and exposed through a window cutout from the distal end of
the sheath. Other types of tissue-cutting element can also be used
in place of the burr 134. Examples of other tissue-cutting elements
will subsequently be described.
The tissue removal probe 110 further comprises a proximal adapter
138 mounted to the proximal end 128 of the sleeve 124. The proximal
adapter 138 is configured to be mated with the drive cable 106,
thereby providing a means for rotatably coupling the drive unit 104
to the proximal end of the drive shaft 132. Thus, operation of the
drive unit 104 will rotate the drive shaft 132, which in turn, will
rotate the burr 134 about its rotational axis 140. Details of the
structure of standard tissue removal probes, including the
aforementioned window-exposed burr and proximal adapter, are
disclosed in U.S. Pat. No. 5,913,867, which is expressly
incorporated herein by reference.
The tissue removal probe 110 is rotatably disposed within the
cannula lumen 118, such that the sleeve 124 (and in particular, the
straight portion of the sleeve) has an axis of rotation 142 (i.e.,
the sleeve 124 can be rotated about the rotational axis 142, e.g.,
when the proximal end 128 of sleeve distal end 126 is manually
rotated). As illustrated in FIG. 9, the rotational axes 140 and 142
of the respective burr 132 and sleeve 124 are coincident with each
other when the entirety of the sleeve 124 is straight. As will be
described in below, the rotational axes 140 and 142 will diverge
from each other when the distal end 126 of the sleeve 124 is curved
or bent.
As illustrated in FIGS. 10-12, the tissue removal probe 110 is
slidably disposed in the cannula lumen 118 in the longitudinal
direction, so that the burr 134 can be incrementally deployed from
the exit port 120 of the cannula shaft 112 and retracted within the
distal end 114 of the cannula shaft 112.
As can be seen from FIG. 10, when confined within the cannula lumen
118, the sleeve 124 assumes a substantially straight configuration
and conforms to the shape of the cannula shaft 112. As can be seen
from FIGS. 11 and 12, the distal end 126 of the sleeve 124, when in
its relaxed state, has a pre-shaped curved portion 144 and a
pre-shaped straight portion 146 distal to the curved portion 144.
In the illustrated embodiment, the curved portion 144 defines an
arc of ninety-degrees. It should be noted, however, the curved
portion 144 may define other arcs. So that the distal end 126 of
the sleeve 124 readily assumes and maintains its defined shape, the
sleeve 124 is composed of a laterally flexible, yet resilient,
material, such as nitinol. Significantly, the drive shaft 132 is
also laterally flexible, and thus easily conforms to the curved
geometry of the deployed sleeve distal end 126. In this manner, the
burr 134 will rotate about its rotational axis 140 even if the
drive shaft 132 is bent.
As can be appreciated from FIGS. 11 and 12, the distal end 126 of
the sleeve 124 can be deployed from the cannula exit port 120 in
stages. For example, the sleeve distal end 126 can be deployed a
first distance from the distal end 114 of the cannula shaft 112, so
that the burr 134 defines a particular radius of revolution r.sub.1
(shown in FIG. 11) around the rotational axis 142 of the sleeve
124. The sleeve distal end 126 can be deployed a second greater
distance from the distal end 126 of the cannula shaft 112, so that
the burr 134 defines a second greater radius of revolution r.sub.2
(shown in FIG. 12) around the rotational axis 142 of the sleeve 124
Thus, it can be appreciated that radius of revolution r of the burr
134 can be adjusted simply by displacing the sleeve 124 within the
cannula lumen 118.
As illustrated in FIG. 13, the tissue removal probe 110 can
optionally have irrigation and aspiration capability. In
particular, the sleeve 124, in addition to having the lumen 130
through which the drive shaft 132 extends, includes irrigation and
aspiration lumens 148 and 150 (shown in phantom). The irrigation
lumen 148 terminates at an irrigation outlet port 152 in the sleeve
distal end 126 and proximally terminates at an irrigation inlet
port (not shown) in the proximal adapter 138. Likewise, the
aspiration lumen 150 terminates at an aspiration entry port 154 in
the sleeve distal end 126 and proximally terminates at an
aspiration outlet port (not shown) in the proximal adapter 138.
Alternatively, irrigation and/or aspiration ports can be placed in
the burr 134.
As can be appreciated, a pump (not shown) can be connected to the
irrigation inlet port on the proximal adapter 138 in order to flush
irrigation fluid, such as saline, through the irrigation lumen 148
and out the irrigation outlet port 152. The irrigation fluid helps
cool the drive shaft 132 and/or the burr 134, while the burr 134 is
rotating at high speed and grinding against tissue. The media also
washes away debris at the target site. A vacuum (not shown) can be
connected to the aspiration outlet port on the proximal adapter 138
in order to aspirate the removed tissue into the aspiration inlet
port 154, through the aspiration lumen 150, and out of the
aspiration outlet port. Because there are separate irrigation and
aspiration lumens 148 and 150, both the pump and aspirator can be
activated simultaneously or separately.
Having described the structure of the tissue removal system 100,
its operation will now be described with reference to FIGS.
14A-14G, in removing soft tissue from an anatomical body, and in
particular, in performing a discectomy on a herniated
intervertebral disc. It should be noted, however, that other
tissue, such as the cancellous tissue within a vertebral body,
could also be removed by the tissue removal system 100.
First, the cannula 108 is introduced through a small incision 41 in
the back 39 and into the herniated disc 12' (FIG. 14A). In some
circumstances, a laminectomy may have to be performed to access the
disc 12'. In such cases, the cannula 108 may be used to bore
through the lamina (not shown). Torsional and/or axial motion may
be applied to the cannula 108 to facilitate boring of the lamina.
The torsional and/or axial motion may be applied manually or
mechanically (i.e., by a machine). An object, such as a hammer or a
plunger, may also be used to tap against the handle 122 of the
cannula 108 in order to facilitate boring through the lamina.
Alternatively, a stilette (not shown) can be introduced through the
cannula lumen (not shown in FIG. 14A) to create a passage through
the lamina. Or, a separate drill or bone cutting device, such as
those described below, can be used to bore or cut a passage through
the lamina prior to placement of the cannula 108.
In the illustrated method, the cannula 108 is introduced into the
disc 12', such that its distal tip is placed adjacent the
distal-most region of the target tissue. In this case, distal to
the herniation 46. Next, the tissue removal probe 110 is introduced
through the cannula lumen 118 until the distal end 126 of the
sleeve 124 deploys out from exit port 120 of the cannula shaft 112
a first distance (FIG. 14B), which as described above, associates
the burr 134 with a first radius of revolution r.sub.1 around the
rotational axis 142 of the sleeve 124. The tissue removal probe 110
can either be introduced into the cannula lumen 118 prior to
introduction of the cannula 108 into the patient's back (in which
case, the tissue removal probe 110 will be fully retracted within
the cannula lumen 118 during introduction of the cannula 108) or
can be introduced into the cannula lumen 118 after the cannula 108
has been introduced into, and properly positioned, within the disc
12'.
Next, the proximal adapter 138 of the tissue removal probe 110 is
mated to the drive unit (shown in FIG. 8), which is then operated
to rotate the burr 134 about is own rotational axis 140. At the
same time, the sleeve 124 is manually rotated (e.g., by rotating
the proximal adapter 138), which causes the burr 134 to scribe an
arc a.sub.1 around the rotational axis 142 of the sleeve 124 (FIG.
14C). As a result, tissue is removed by the rotating burr 134 along
the arc a.sub.1. In the illustrated method, the sleeve 124 is
rotated until the burr 134 scribes an entire circle around the
rotational axis 142 of the sleeve 124. In this manner, a full
circle of tissue is removed by the burr 134. In the illustrated
method, the radius of revolution of the burr 134 is so short that
both on-axis and off-axis tissue is essentially removed. In effect,
the burr 134 removes a small disc of tissue at this point. It
should be noted that, during the tissue removal procedure, the
removed tissue could be aspirated from the herniated disc 12' using
an aspirator. Aspiration of the tissue can be accomplished via the
cannula or through another cannula. Alternatively, as previously
described, aspiration can be accomplished via the tissue removal
probe 110, itself.
Next, the tissue removal probe 110 is further introduced through
the cannula lumen 118 until the distal end 126 of the sleeve 124
deploys out from the exit port 120 of the cannula shaft 112 a
second greater distance (FIG. 14D), which as described above,
associates the burr 134 with a second greater radius of revolution
r.sub.2 around the rotational axis 142 of the sleeve 124. Again,
the drive unit 104 is operated to rotate the burr 134 about is own
rotational axis 140, while manually rotating the sleeve 124, which
causes the burr 134 to scribe another larger arc a.sub.2 around the
rotational axis 142 of the sleeve 124 (FIG. 14E). As a result, a
ring of tissue is removed by the rotating burr 134 along the larger
arc a.sub.2. Again, the sleeve 124 is rotated until the burr 134
scribes an entire circle around the rotational axis 142 of the
sleeve 124. In this manner, a full circle of tissue is removed by
the burr 134. The difference between the first and second radii and
of revolution r.sub.1 and r.sub.2 is such that the disc of tissue
removed by the burr 134 along the first arc a.sub.1 is coextensive
with the ring of tissue removed by the burr 134 along the second
arc a.sub.2. The steps illustrated in FIGS. 14D and 14E can be
repeated to remove even larger discs of tissue.
Next, the cannula 108 is displaced in the proximal direction, and
the tissue removal probe 110 is retracted, so that the sleeve
distal end 126 deploys out from the exit port 120 of the cannula
shaft 112 the first distance (FIG. 14F). The steps illustrated in
FIGS. 14B-14E are then repeated to remove another disc of tissue
(FIG. 14G). In the illustrated method, the proximal displacement of
the cannula 108 is such that the first and second discs of removed
tissue are contiguous. As such, a cylinder of tissue is removed. A
longer cylinder of tissue can be removed by repeating the steps
illustrated in FIGS. 14F and 14G. After the discectomy has been
completed (i.e., the herniated disc material has been removed, or
in some cases, the entire herniated disc has been removed), the
cannula 108, along with the tissue removal probe 110, is removed
from the patient's body. Alternatively, prior to total removal of
the cannula 108, the tissue removal probe 110 can be removed, and a
therapeutic media, such as a drug or disc replacement material can
be delivered through the cannula lumen 118 into the disc 12'.
Although curved portion 144 of the sleeve distal end 126 is
pre-shaped in order to create a radius of revolution r for the
deployed burr 134, there are other means for bending the distal end
of a sleeve as it deploys from a cannula. For example, FIGS. 15-17
illustrate a tissue removal assembly 202 that bends a deploying
sleeve using the cannula, itself. In particular, the tissue removal
assembly 202 comprises a cannula 208, which is similar to the
previously described cannula 108, with the exception that it
comprises a cannula shaft 212 with a curved distal end 214. In the
illustrated embodiment, the distal end 214 of the cannula 208
assumes a ninety-degree curve. The tissue removal assembly 202
comprises a tissue removal probe 210 that is similar to the
previously described tissue removal probe 110, with the exception
that it comprises a sleeve 224 that does not have a pre-curved
distal end. Instead, the entire sleeve 224 is configured to assume
a straight configuration in its relaxed state.
As can be seen from FIG. 15, when confined within the cannula lumen
218, the sleeve 224 assumes a substantially straight configuration
and conforms to the shape of the cannula shaft 212. As can be seen
from FIGS. 16 and 17, the distal end 226 of the sleeve 224 bends
when deployed from the distal end of the cannula shaft 112. That
is, as it is deployed, the sleeve distal end 226 contacts the inner
surface of the curved cannula distal end 214, thereby deflecting
the sleeve distal end 226 as its exits the cannula lumen 218. Like
the previously described sleeve 124, the sleeve is laterally
resilient, such that it maintains its shape as it deploys from the
exit port 220 at the distal end 214 of the cannula shaft 212.
As with the previously described sleeve distal end 126, the sleeve
distal end 226 can be deployed from the exit port 220 of the
cannula shaft 212 in stages. For example, the sleeve distal end 226
can be deployed a particular distance from exit port 220, so that
the burr 134 defines a particular radius of revolution r.sub.1
(shown in FIG. 16) around the rotational axis 242 of the sleeve
224. The sleeve distal end 226 can be deployed a second greater
distance from the exit port 220, so that the burr 134 defines a
second greater particular radius of revolution r.sub.2 (shown in
FIG. 17) around the rotational axis 242 of the sleeve 224. Thus, it
can be appreciated that radius of revolution r of the burr 134 can
be adjusted simply by displacing the sleeve 224 within the cannula
lumen 218.
Operation of the tissue removal assembly 202 in removing soft
tissue is similar to the operation of the previously described
tissue removal assembly 102, and will thus, not be further
described.
As another example, FIGS. 30-33 illustrate a tissue removal
assembly 252 that has a sleeve with steering functionality. In
particular, the tissue removal assembly 252 comprises the
previously described cannula. 108, and a tissue removal probe 260
that is similar to the previously described tissue removal probe
110, with the exception that it does not have a pre-curved distal
end, but instead, comprises a pair of pull wires 254 (shown in FIG.
31) extending through a respective pair of pull wire lumens 256
contained within the sleeve 124. The distal ends of the pull wires
254 are mounted to the distal tip of the sleeve 124 in a suitable
manner. As can be seen from FIG. 30, when confined within the
cannula lumen 218, the sleeve 124 assumes a substantially straight
configuration and conforms to the shape of the cannula shaft 112.
As can be seen from FIGS. 32 and 33, the distal end 126 of the
sleeve 124, when deployed from the exit port 120 of the cannula
shaft 112, bends in one direction when one of the pull wires 254 is
pulled.
As with the previously described tissue removal probe 110, the
sleeve distal end 126 can be deployed from the exit port 120 of the
cannula shaft 112 in stages. For example, the sleeve distal end 126
can be deployed a first distance from exit port 120 and one of the
pull wires 254 pulled to bend the sleeve distal end 126, so that
the burr 134 defines a particular radius of revolution r.sub.1
(shown in FIG. 32) around the rotational axis 142 of the sleeve
124. The sleeve distal end 126 can be deployed a second greater
distance from the exit port 120 and the pull wire 254 pulled to
bend the sleeve distal end 126 again, so that the burr 134 defines
a second greater particular radius of revolution r.sub.2 (shown in
FIG. 33) around the rotational axis 142 of the sleeve 124. Thus, it
can be appreciated that radius of revolution r of the burr 134 can
be adjusted simply by displacing the sleeve 124 within the cannula
lumen 118 and pulling one of the pull wires 254 to bend the sleeve
distal end 126.
Operation of the tissue removal assembly 252 in removing soft
tissue is similar to the operation of the previously described
tissue removal assembly 102, with the exception that the pull wires
254 are used to actively bend the distal end 126 of the sheath
124.
Alternatively, as illustrated in FIGS. 34A-34F, the tissue removal
assembly 252 may be used in a different manner to remove soft
tissue from an anatomical body, and in particular, in performing a
discectomy on a herniated intervertebral disc. This alternative
method is accomplished by bending the distal end 126 of the sleeve
124 in opposite directions using the pull wires 254, while rotating
the burr 134, thereby removing tissue in an arc that is coplanar
with the plane of the axis 142. In this case, a layer of tissue is
removed in a plane that is parallel with the flat sides of the
herniated disc.
In particular, after the cannula 108 is introduced into the
herniated disc 12' in the same manner previously illustrated in
FIG. 14A, the tissue removal probe 260 is introduced through the
cannula lumen 118 until the distal end 126 of the sleeve 124
deploys out from exit port 120 of the cannula shaft 112 a first
distance (FIG. 34A), which associates the burr 134 with a first
radius of curvature r.sub.1 (shown in FIG. 34B). Next, the proximal
adapter 138 of the tissue removal probe 210 is mated to the drive
unit (shown in FIG. 8), which is then operated to rotate the burr
134 about is own rotational axis 140. At the same time, the distal
end 126 of the sleeve 124 is bent in one direction by pulling one
of the pull wires 254 (shown in FIG. 34A), which causes the
rotating burr 134 to scribe a ninety degree arc a.sub.1 (as
measured from the longitudinal axis 142) around the distal tip of
the sleeve 124 (FIG. 34B). Next, the distal end 126 of the sleeve
124 is bent in the opposite direction by pulling the other pull
wire 254, which causes the rotating burr 134 to scribe a one
hundred eighty degree arc a.sub.1 (ninety degrees above the
longitudinal axis 142 and ninety degrees below the longitudinal
axis 142) around the distal tip of the sleeve 124 (shown in phantom
in FIG. 34B). In this manner, a semi-circle of tissue is removed by
the burr 134. In the illustrated method, the radius of curvature of
the burr 134 is so short that a solid radial sector of tissue is
removed. As with the previous methods, the remove tissue can
optionally be aspirated.
Next, the tissue removal probe 210 is further introduced through
the cannula lumen 118 until the distal end 126 of the sleeve 124
deploys out from the exit port 120 of the cannula shaft 112 a
second greater distance (FIG. 34C), which associates the burr 134
with a second greater radius of curvature r.sub.2 (shown in FIG.
34D). Again, the drive unit 104 is operated to rotate the burr 134
about is own rotational axis 140, while bending the distal end 126
of the sleeve 124 in one direction using the first pull wire 254
(shown in FIG. 34C), which causes the burr 134 to scribe another
larger ninety degree arc a.sub.2 around the distal tip of the
sleeve 124 (FIG. 34D). Next, the distal end 126 of the sleeve 124
is bent in the opposite direction by pulling the other pull wire
254, which causes the rotating burr 134 to scribe a one hundred
eighty degree arc a.sub.2 around the distal tip of the sleeve 124
(shown in phantom in FIG. 34D). In this manner, a semi-circular
ring of tissue is removed by the burr 134.
The difference between the first and second radii and of curvature
r.sub.1 and r.sub.2 is such that the radial sector of tissue
removed by the burr 134 along the first arc a.sub.1 is coextensive
with the semi-circular ring of tissue removed by the burr 134 along
the second arc c.sub.2. The steps illustrated in FIGS. 34C and 34D
can be repeated to remove even larger discs of tissue.
After the discectomy has been completed (i.e., the herniated disc
material has been removed, or in some cases, the entire herniated
disc has been removed), the cannula 108, along with the tissue
removal probe 110, is removed from the patient's body.
Alternatively, prior to total removal of the cannula 108, the
tissue removal probe 260 can be removed, and a therapeutic media,
such as a drug or disc replacement material can be delivered
through the cannula lumen 118 into the disc 12'.
Referring now to FIGS. 18 and 19, another tissue removal probe 310
that can alternatively be used in the tissue removal system 100
will be described. The tissue removal probe 310 comprises a sleeve
324 having a distal end 326 and a proximal end 328, and a lumen 330
(shown in phantom in FIG. 18) extending through the sleeve 324. The
tissue removal probe 310 further comprises a drive shaft 332
rotatably disposed within the sleeve lumen 330 and a rotatable
tissue removal element, and in particular, a rotatable cutting
basket 334, mounted to the distal end of the drive shaft 332. The
tissue removal probe 310 further comprises a proximal adapter 338
mounted to the proximal end 328 of the sleeve 324. The proximal
adapter 338 is configured to be mated with the drive cable 106,
thereby providing a means for rotatably coupling the drive unit 104
to the proximal end of the drive shaft 332. Thus, operation of the
drive unit 104 will rotate the drive shaft 332, which, in turn,
will rotate the cutting basket 334 about its rotational axis 340.
Like the tissue removal probe 110, the tissue removal probe 310 can
be rotatably disposed within the lumen 118 of the cannula 108, so
that the cutting basket 334 can be alternately deployed from and
retracted into the distal end 114 of the cannula shaft 112.
The cutting basket 334 comprises a base member 344, a distal hub
346, and a plurality of filaments 348 proximally affixed to the
base member 344 and distally affixed to the distal hub 346. The
base member 344 is mounted to the distal end of the drive shaft 332
using suitable means, such as soldering or welding. The distal hub
346 is preferably rounded, such that only lateral tissue removal is
achieved, and inadvertent tissue trauma distal to the cutting
basket 334 is prevented. As shown in FIGS. 18 and 19, the shape of
the filaments 348 is sinusoidal, although other shapes can be
provided. Although three filaments 348 are shown, the cutting
basket 334 may include a different number of filaments 348. The
filaments 348 are also interlaced or braided to provide the cutting
basket 334 with a more integral structure.
In alternative embodiments, however, the filaments 348 can
configured differently. For example, FIG. 20 illustrates an
alternative cutting basket 354, wherein the filaments 348, the
proximal and distal ends of which are mounted to the base member
344, thereby affixing the filaments 348 at the proximal end of the
cutting basket 334. The filaments 348 are affixed at the distal end
of the cutting basket 334 by looping the filaments 348 through the
distal hub 346.
Whichever filament configuration is used, the cross-sectional shape
of each filament 348 can be circular, rectangular, elliptical, or
other customized shapes. As can be appreciated, the large spaces
between the filaments 348 prevent, or at the least minimize, the
build-up of tissue on the cutting basket 334. If bone tissue is to
be removed, the filaments 348 are preferably made from a tough
material, such as steel or other alloys, so that it could penetrate
or cut into a bone structure without being damaged. The stiffness
of the filaments 348 are preferably selected so that the cutting
basket 334 is stiff enough to cut, deform, and/or compact target
bone tissue. In the case where soft tissue is to be removed, the
filaments 348 may likewise be composed of a soft material. In any
event, the material from which the filaments 348 are made are
resilient, such that cutting basket 334 assumes a low profile while
residing within the cannula lumen 330, and is free to assume an
expanded profile when deployed outside of the cannula lumen 330. In
the illustrated embodiment, the cutting basket 334 is 1 cm in
length and 1/2 cm in diameter.
In some embodiments, the filaments 348 have sharp edges, thereby
providing bone, disc or soft tissue cutting/drilling capability. In
other embodiments, the cutting basket 334 includes abrasive
particles, such as diamond dusts, disposed on surfaces of the
filaments 348, for cutting, digging, and/or sanding against target
bone, disc or soft tissue. The filaments 348 are connected between
the base member 344 and distal hub 346 and drive shaft 332 using
means, such as a welding, brazing, or glue, depending on the
materials from which the distal hub, filaments, and drive shaft 332
are made. Alternatively, the filaments 348 are connected between
the distal hub 346 and drive shaft 332 by a snap-fit connection, a
screw connection, or otherwise an interference-fit connection.
The tissue ablation probe 310 optionally comprises a guidewire 352
that extends through a lumen 353 (shown in phantom) within the
drive shaft 332, and is mounted to the distal hub 346 of the
cutting basket 334. In this manner, the lateral movement of the
cutting basket 334 during operation is limited.
Referring now to FIG. 21, still another tissue removal probe 410
that can alternatively be used in the tissue removal system 100
will be described. The tissue removal probe 410 is similar to the
previously described tissue removal probe 310 in that it comprises
the sleeve 324, drive shaft 332, and proximal adapter 338. The
tissue removal probe 410 differs from the tissue removal probe 310
in that it comprises a tissue removal device, and in particular, a
cutting basket, that can be transformed between a tissue-cutting
device and a tissue grasper.
In particular, the cutting basket 434 comprises a base member 444,
a distal hub 446, and a plurality of filaments 448 proximally
affixed to the base member 444 and distally affixed to the distal
hub 446. The base member 444 is mounted to the distal end of the
drive shaft 332 using suitable means, such as soldering or welding.
The distal hub 446 is preferably rounded, such that only lateral
tissue removal is achieved, and inadvertent tissue trauma distal to
the cutting basket 434 is prevented. The filaments 448 may have the
same composition as the previously described filaments 448.
Each filament 448, however, has a hinge point 450 that divides the
filament 448 into a proximal filament segment 452 and a distal
filament segment 454. As shown in the progression illustrated in
FIGS. 22A-22D, pulling the distal hub 446 in the proximal direction
causes the distal end of the cutting basket 434 to invert into the
proximal end of the cutting basket 434. That is, the distal
filament segments 454 fold around the hinge points 450 towards the
proximal filament segments 452, transforming the folded filaments
448 into tissue-grasping arms, with the hinge points 450 forming
the most distal points of the arms. Notably, the hinge points 450
are located distal to the midpoints of the filaments 448 (i.e., the
distal filament segments 454 are shorter than the proximal filament
segments 452). In this manner, the resulting tissue-grasping arms
are relatively short, and therefore have a greater resistance to
lateral bending when grasping tissue.
The actuating device takes the form of a pull wire 456 that extends
through the lumen 353 in the drive shaft 332, attaching to the
distal hub 446. Thus, when the pull wire 456 is pulled, the cutting
basket 434 is transformed from a tissue-cutting device to a
tissue-grasping device. When the pull wire 456 is relaxed, the
tissue-grasping device (due to its resiliency) reverts back to a
tissue-cutting device. That is, the distal filament segments 454
will fold back around the hinge points 450 away from the proximal
filament segments 452, transforming the filaments 448 into
tissue-cutting filaments.
Referring now to FIGS. 23 and 24, yet another tissue removal probe
510 that can alternatively be used in the tissue removal system 100
will be described. The tissue removal probe 510 is similar to the
previously described tissue removal probe 310 in that it comprises
the sleeve 324 and proximal adapter 338. The tissue removal probe
510 differs from the tissue removal probe 310 in that it has tissue
irrigating functionality and minimizes inadvertent trauma to distal
tissue, otherwise caused by a tissue removal element 534.
In particular, the tissue removal probe 510 comprises a drive shaft
532, which is composed of a rigid material, such as stainless
steel, and has a distal end with a non-traumatic blunt tip 536. The
blunt tip 536 prevents the tissue removal element 534 from abrading
or harming distal tissue during use. In the illustrated embodiment,
the blunt tip 536 has a spherical shape. In alternative
embodiments, however, the blunt tip 536 can have other shapes as
well. The drive shaft 332 further comprises an irrigation lumen 538
(shown in phantom) that terminates in an irrigation port 540 at the
blunt tip 536. As previously described, irrigation fluid can be
delivered through the irrigation lumen 538 and out of the
irrigation port 540 in order to cool the drive shaft 332 and/or
tissue removal element 534, as well as to wash debris at the target
site. The irrigation lumen 538 can alternatively be used as a
guidewire lumen.
The tissue removal element 534 is formed on the distal end of the
drive shaft 332 just proximal to the blunt tip 536. In the
illustrated embodiment, the tissue removal device 534 comprises an
ellipsoidal burr, although other geometrically shaped burrs can be
used. Unlike a cutting basket, the cross-section of the burr 534 is
relatively more solid, thereby providing more stiffness. Such
configuration is advantageous in that it allows cutting and/or
abrading of stiff materials without deforming. In the illustrated
embodiment, the burr 534 includes abrasive particles, such as
diamond dusts, that are disposed on the surface of the burr 534. In
other embodiments, instead of having diamond dusts, parts of the
surface of the burr 534 can be removed to create an abrasive
surface. The burr 534 further comprises a spiral cutting groove
542. During use, the groove 542 allows bone particles that have
been removed to travel proximally and away from a target site.
Referring now to FIG. 25, yet another tissue removal probe 610 that
can alternatively be used in the tissue removal system 100 will be
described. The tissue removal probe 610 is similar to the
previously described tissue removal probe 310 in that it comprises
the sleeve 324, drive shaft 332, and proximal adapter 338. The
tissue removal probe 610 differs from the tissue removal probe 310
in that it comprises a tissue removal element 634 with
counter-pitched grooves.
In particular, the tissue removal element 634 is mounted to the
distal end of the drive shaft 332, and takes the form of a
cylindrically-shaped burr with proximal spiral cutting grooves 636
and distal spiral cutting grooves 638. The respective proximal and
distal grooves 636 and 638 are oppositely pitched, such the removed
tissue is force to travel along the grooves 636/638 towards the
center of the burr 634 when rotated in a particular direction (in
this case, clockwise if looking down the distal end of the burr
634). In this manner, the removed tissue will tend to be collected
in one place, thereby making aspiration of the tissue easier.
Referring now to FIG. 26, yet another tissue removal probe 710 that
can alternatively be used in the tissue removal system 100 will be
described. The tissue removal probe 710 is similar to the
previously described tissue removal probe 610 with the exception
that two counter-rotating burrs are used.
In particular, the tissue removal probe 710 comprises an outer
drive shaft 732 with a lumen 736, and an inner drive shaft 733
disposed within the outer drive shaft lumen 736. As such, the drive
shafts 732 and 733 are independent, and can thus be rotated in
opposite directions or the same direction. The tissue removal probe
710 further comprises proximal and distal removal elements 734 and
735 in the form of cylindrical burrs mounted to the distal ends of
the respective drive shafts 732 and 733. The cylindrical burrs 734
and 735 are collinear and coextensive with each other, so that they
can operate as a contiguous tissue removal device. Spiral cutting
grooves 738 and 740 are formed in the surfaces of the respective
burrs 734 and 735 In the illustrated embodiment, the absolute pitch
of the spiral grooves 738 on the proximal burr 734 is the same as
the absolute pitch on the distal burr 735. The grooves 738/740,
however, are pitched in the opposite direction. Thus, rotation of
the proximal burr 734 in one direction (by rotating the outer drive
shaft 732 in that direction), and rotation of the distal burr 735
in the opposite direction (by rotating the inner drive shaft 733 in
that direction) will stabilize the tissue removal probe 710 as it
is laterally cutting through tissue, e.g., bone tissue. That is,
the counter-rotating burrs 734/735 prevents, or at least minimizes,
the tendency of the tissue removal probe 710 to stray from its
intended cut path.
Alternatively, the burrs 734/735 can be rotated in the same
direction, preferably in a direction that forces the removed tissue
to travel along the grooves 738/740 of the respective burrs 734/735
towards the interface between the burrs 734/735. In this manner,
the removed tissue will tend to be collected in one place, thereby
making it more easily aspirated. Thus, it can be appreciated that
the independence of the outer and inner drive shafts 732/733,
allows the respective burrs 734/735 to be selectively rotated in
opposite directions or rotated in the same direction.
Referring now to FIG. 27, yet another tissue removal probe 810 that
can alternatively be used in the tissue removal system 100 will be
described. The tissue removal probe 810 is similar to the
previously described tissue removal probe 310 in that it comprises
the sleeve 324, drive shaft 332, and proximal adapter 338. The
tissue removal probe 810 differs from the tissue removal probe 310
in that it comprises a tissue removal element 834 configured to
drill holes through bone, whereas the tissue removal element of the
tissue removal probe 310, as well as those subsequently described
in tissue removal probes 410, 510, 610, and 710, lend itself well
to the lateral removal of hard bone tissue, e.g., during
laminectomy and laminotomy procedures.
In particular, the tissue removal element 834 takes the form of a
drill bit mounted at the distal end of the drive shaft 332. The
drill bit 834 has a sharp distal tip 836 that allows the rotating
drill bit 834 to penetrate or shape bone tissue. In the illustrated
embodiment, the drill bit 834 has a length that is between 1/4 and
1 inch, and a diameter that is between 1/100 and 1/2 inch. The
drill bit 834 includes two fluted cutting grooves 838 that extend
down opposite sides of the drill bit 834, as shown in FIG. 28.
Referring now to FIG. 29, yet another tissue removal probe 910 that
can alternatively be used in the tissue removal system 100 will be
described. Unlike in the previously described embodiments, which
have rotatable tissue removal elements, the tissue removal probe
910 comprises a reciprocating tissue removal element. In
particular, the tissue removal probe 910 comprises a rigid drive
shaft 912 having a distal end 914, and a tissue removal element 934
formed on the distal end 914 of the drive shaft 912. The tissue
removal element 934 comprise a block 936 with a series of cascading
tissue-cutting notches 938 longitudinally formed along the block
934. As a result, a series of sharp leading edges 940 are formed
along the block 934. In the illustrated embodiment, the block 936
has a rectangular cross-section.
Thus, it can be appreciated that the tissue removal element 934 can
be placed within a hole or groove in a bone, and reciprocatably
moved to remove bone tissue from the bone, thereby enlarging the
hole. A motor can be configured to apply a hammering motion (i.e.,
a forward and rearward motion) to drive the shaft 912.
Although particular embodiments of the present invention have been
shown and described, it should be understood that the above
discussion is not intended to limit the present invention to these
embodiments. It will be obvious to those skilled in the art that
various changes and modifications may be made without departing
from the spirit and scope of the present invention. In addition, an
illustrated embodiment needs not have all the aspects or advantages
of the invention shown. An aspect or an advantage described in
conjunction with a particular embodiment of the present invention
is not necessarily limited to that embodiment and can be practiced
in any other embodiments of the present invention even if not so
illustrated. Thus, the present invention is intended to cover
alternatives, modifications, and equivalents that may fall within
the spirit and scope of the present invention as defined by the
claims.
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